Bollettino valanghe

Mount Shasta

Mount Shasta Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Dangerous avalanche conditions exist near and above treeline. Strong-extreme westerly wind has been loading N-NE-E-SE-S aspects for the past 48 hours with all available soft snow. With more snow and wind expected in the next 24 hours, the instability will only continue. Human-triggered avalanches are likely, and natural avalanches are possible. Today, careful snowpack/weather assessment and conservative decision-making will be crucial for backcountry travelers. If in doubt, avoid any slopes greater than 30 degrees.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    The primary area for wind slab development is near and above treeline, where most of the soft snow has been completely scoured from windward (westerly) slopes, and deposited onto leeward aspects. Expect to find this problem on N-NE-E-SE-S aspects, with cross loading on NW and SW aspects. These slabs are reactive to trigger, and could break two to three feet deep and hundreds of feet wide. With more wind and snow on the way, it's possible that wind loaded areas release naturally. Below treeline, the wind has had minimal effect on the surface snow. That being said, light wind effect and small hollow slabs could still be found yesterday in this terrain. If headed into the backcountry today, assess avalanche terrain carefully. Wind loaded slopes could be quite sensitive to trigger. If in doubt, avoid slopes greater than 30 degrees. 

Avalanche Discussion

Today will bring very similar conditions to the last couple of days, with a few key changes:

First, the wind. The strong westerly wind has now been blowing for two days straight, moving a lot of soft snow onto leeward slopes. This is expected to continue with more snow arriving this evening. At the moment, a large wind slab avalanche is yet to be seen through this storm cycle. But just because it hasn't been seen, doesn't mean it isn't out there. More than likely, these leeward slopes (N-NE-E-SE-S) are overloaded, and nearing the tipping point of human-trigger or natural release. Remember, wind slabs can often develop in low and unexpected areas. Keep a sharp eye out there, and diligently look for signs of instability.

Second, the warming trend. A warm-up is currently underway, lifting snow levels from 4,800 feet (yesterday), to 8,100 by tomorrow. As of 6am this morning, Gray Butte (8,000 feet), is recording 28 degrees F and climbing. Rain-on-snow will occur below treeline, resulting in an upside down snow structure across all aspects. Surface snow will shift from cold and dry, to a wet and sticky mess by tomorrow. 

Regioni coperte